The present invention relates to a printing apparatus in which information regarding the format of print control data including an amount of print pitch, line feed, etc., is set by operating various kinds of switches provided on the operation panel. Alternatively, this information is changed in response to a command from the outside and the printing operation is controlled in accordance with this information.
Hitherto, there is known a printing apparatus in which the switch data corresponding to the states of the various kinds of switches on the operation panel is read only when a power source is turned on, and all of the print control data including the information regarding the automatic line feed, moving amount of a carrier, line feed amount, paper length, etc., are set in accordance with this switch data, and the reading operation is not performed during the operation. Also, in a printing apparatus, when the operation mode changes from the off-line state to the on-line state even during the operation or when a power source is turned on, various kinds of switch data of the operation panel are read and all of the print control data are set in accordance with this switch data. The operation mode is switched from the on-line state to the off-line state when the printing apparatus is set in an error state or not-ready state due to a paper end, cover open of the printing section or the end of an ink ribbon. When the printing apparatus is temporarily disconnected from a host computer to control this printing apparatus by a command from the outside, or when a paper feed is performed by a manual operation of a switch on the operation panel. When these states are recovered to the original states, the operation mode of this printing apparatus is switched from the off-line state to the on-line state. In this kind of printing apparatus, the print control data includes data which can be changed only by a command from the outside and data which cannot be changed by a command but can be changed only by a switch on the operation panel. Thus, in the printing apparatus which can change the information only when the power source is turned on, in order to change the print control data which cannot be changed by the external command, it is required to turn off the power source and then change over the switch, and thereafter turn on the power source again. In addition, when the power source is again turned on, all of the print control data are changed on the basis of the various kinds of switch states of the operation panel; therefore, when the print control data is changed by the command, a command has to be again sent to this printing apparatus from the host computer in order to set this print control data. On the other hand according to the printing apparatus, the print control data is changed when the power source is turned on and when the operation mode is changed to the on-line state. In case of changing the print control data which cannot be changed by the command, there is no need to again turn on the power source. However, when the operation mode is changed from the off-line state to the on-line state, all of the data are changed on the basis of the switch states of the operation panel similarly to the case where the power source is turned on. Consequently, if the print control data is changed by the external command, this print control data has to be changed by again sending the command from the outside.